Eh, it depends on the kind of player. The optimal player (who can play a lot and plays well) earns 12 frags/month and 4 chests/month so it works out exactly even. I pretty much earn my chests the day they unlock, but I don't always play enough in a given month to cap out on fragments, so I've got like 3 chests I won't be able to open for a looong time (although eventually, since key frags seem to sometimes be event rewards, and the multiple fragments from a capsule only counts as one fragment drop).
Other players play tons but are hard mains who might get a ton of keys but just the one chest, but then they probably don't really need keys/chests to begin with as it's very unlikely to get a skin for the specific champ they one-trick, not to mentioned if they're that focused they may have just got the skin directly.
Still, people being short orange essence for something they do want can be a pain. No guarantee that they don't just get a champ shard even if you could gift chests though, so it wouldn't necessarily be a solution to that particular issue.